LC-MS analyses revealed significant metabolic changes associated with the docosahexaenoic acid supplementation in rats.

Evidences suggest that dietary docosahexaenoic acid (DHA) supplementation may have pleiotropic beneficial effects on health. However, the underlying mechanisms and crucial targets that are involved in achieving these benefits remain to be clarified. In this study, we employed biochemical analysis and liquid chromatography-mass spectrometry (LC-MS) based untargeted metabolomics coupled with multivariate statistical analysis to identify potential metabolic targets of DHA in adult rats at 48 h post-feeding. Blood biochemical analysis showed a significant decrease in triglyceride level of DHA diet group, the untargeted metabolomic analysis revealed that some metabolites were significantly different between the DHA diet group and the basal diet group, including fatty acids (16:0, 18:1, 20:5n3, 22:2n6 and 24:0), diglyceride (20:0/18:2n6, 18:3n6/22:6n3, 20:4n3/20:4n3, and 22:0/24:0), PIP2 (18:2/20:3), phytol, lysoSM (d18:1), 12-hydroxyheptadecatrienoic acid, dihydrocorticosterone and N1-acetylspermine, which are mainly involved in fat mobilization and triglyceride hydrolysis, arachidonic acid, steroid hormone, and polyamine metabolism. To our knowledge, this is the first report that links the metabolic effects of DHA with arachidonic acid, steroid, and polyamine metabolism. Our finding suggests that the beneficial effects of DHA, may not directly require its own metabolic derivatives, but could be achieved by metabolic regulation.

Effects of switching from sevelamer hydrochloride to bixalomer on laboratory parameters in hemodialysis patients.

In Japan, the clinical use of bixalomer, a new polymer preparation like sevelamer hydrochloride, became possible from 2012. In our study, in order to investigate the clinical characteristics of this new phosphorus (P) binder, bixalomer in a clinical practice, for 18 cases of hemodialysis patients at our hospital being treated with sevelamer hydrochloride, we switched the P binder to bixalomer, and compared the laboratory parameters before and after switching. Subjects used for analysis were nine cases in which it was possible to use bixalomer continuously for 10 months. The laboratory parameters measured were the concentrations of serum P, corrected calcium (Ca), whole parathyroid hormone (PTH), albumin and alkaline phosphatase (ALP) as indicators of mineral and bone disorder, and serum high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) as indicators of lipid metabolism. Regarding the results after switching to bixalomer and starting treatment using the same dosage as the dosage previously used for sevelamer hydrochloride, there were many cases that showed increasing P concentrations that required increasing the dosage of bixalomer, the dosage after switching was increased significantly (P=0.002). In the comparison of laboratory parameters before and after switching, the concentrations of serum P and albumin decreased significantly (P=0.035 and 0.033). From these results, it was considered that the decreases in serum P concentrations were due not only to the effects of bixalomer, but that suppression of food intake by patients was another reason. There were no significant changes in corrected Ca, whole PTH or ALP. In addition, after changing the P binder, serum HDL-C concentration decreased significantly (P=0.015) and LDL-C increased significantly (P<0.001), and serum TG concentration showed no significant changes. This indicated that the beneficial effects of bixalomer on lipid metabolism may be less than those of sevelamer hydrochloride.

Clinical effects of the new phosphorus binder, bixalomer in hemodialysis patients switched from sevelamer hydrochloride.

It has been reported that sevelamer hydrochloride, which is often used as a polymer phosphorus (P) binder for managing serum P concentration in dialysis patients, causes gastrointestinal adverse effects such as constipation, etc. The reason for this is thought to be that sevelamer hydrochloride has high water absorption, causing it to absorb water and swell in the gastrointestinal tract. In June 2012, the new polymer P binder bixalomer was launched in Japan. Since bixalomer has low swelling due to water absorption, it can be expected to alleviate adverse effects in the gastrointestinal system. In our study, for 21 cases of maintenance hemodialysis patients undergoing treatment with sevelamer hydrochloride at our hospital, the P binder was switched from sevelamer hydrochloride to the same dosage of bixalomer, and the concentrations of serum P, corrected calcium (Ca) and whole parathyroid hormone (PTH) before and one month after the switch were compared. In addition, gastrointestinal symptoms (acid reflux, abdominal pain, indigestion, diarrhea and constipation) were evaluated before and after the switch using a questionnaire based on the Japanese version of the Gastrointestinal Symptom Rating Scale (GSRS). By switching to bixalomer, serum P concentration was significantly reduced (P=0.024), but there were no significant changes observed for serum corrected Ca and whole PTH. Furthermore, there were no significant changes observed for all five of the evaluation items of the GSRS, before and after the switch. These results suggest that although bixalomer can more potently reduce the serum P concentration than sevelamer hydrochloride, there were no significant differences in the effects of both P binders on the gastrointestinal symptoms.

Clinical experiences of bixalomer usage at our hospital.

In 2012, bixalomer was launched as new non-calcium (Ca) containing phosphorus (P) binder, increasing the choices available for the treatment of hyperphosphatemia. In this study, among the maintenance dialysis patients at our hospital, we newly administered bixalomer to 21 patients who were not receiving any P binders, and switched to bixalomer for 13 patients who had been receiving sevelamer hydrochloride and 23 patients who had been receiving lanthanum carbonate. The initial dosage of bixalomer was set as 1500 mg/day for new administration patients and dosage equivalent to that of the previously-used P binder for patients who were switched to bixalomer. The dosage of bixalomer was increased if the effects were insufficient. The serum P, Ca and intact parathyroid hormone concentrations as well as serum pH, HCO3 concentration and base excess were evaluated prior to administering bixalomer, 3 months and 6 months after administering bixalomer. For the group who were newly administered bixalomer, significant reductions in serum P concentrations were seen (P<0.01) and no significant changes were seen in clinical test items that serve as indices for acidosis. For the group who were switched from sevelamer hydrochloride to bixalomer, significant reductions in serum P concentrations were seen (P<0.01) together with significant improvements in acidosis (P<0.01). For the group who were switched from lanthanum carbonate to bixalomer, by increasing the dosage of bixalomer to approximately three times the dosage of lanthanum carbonate, it was possible to maintain post-switch serum P concentrations at almost the same levels as before the switch. Furthermore, there were minor, yet significant improvements in acidosis (P<0.01). From these results, it was shown that bixalomer can be useful treatment alternative in dialysis patients for whom it is necessary to change the P binder due to insufficient management of serum P concentrations or development of acidosis.

Dose-finding study of bixalomer in patients with chronic kidney disease on hemodialysis with hyperphosphatemia: a double-blind, randomized, placebo-controlled and sevelamer hydrochloride-controlled open-label, parallel group study.

Hyperphosphatemia is a prognostic factor for morbidity and mortality in chronic kidney disease. Bixalomer (Kiklin® Capsules) is a non-absorbable polymer that decreases serum phosphate levels by binding phosphate in the gastrointestinal tract. This study was a multicenter, double-blind, randomized, placebo-controlled study to confirm the superiority of bixalomer to placebo for a 4-week treatment period in patients with chronic kidney disease on hemodialysis with hyperphosphatemia. Sevelamer hydrochloride (HCl), a similar non-absorbable polymer, was used as an active comparator for open-label as a reference without statistical comparison for efficacy and safety. The primary endpoint was the change in serum phosphorus level from baseline. The safety profile was also investigated. The number of subjects was 32 in the placebo group and 31 in each bixalomer group (1.5, 3.0 and 4.5 g/day), respectively. The baseline serum phosphorus level was 7.95 to 8.25 mg/dL. Bixalomer showed a significant decrease in serum phosphorus level at all doses compared with placebo, and the adjusted mean change in serum phosphorus level from the baseline to the end of treatment (at Week 4 or at the time of discontinuation) was +0.24 mg/dL in the placebo group, -0.75 mg/dL in the 1.5 g/day group, -1.32 mg/dL in the 3.0 g/day group, and -1.80 mg/dL in the 4.5 g/day group, showing a dose-dependent decrease in serum phosphorus level. The mean change in serum phosphorus level was -2.32 mg/dL in the sevelamer HCl group under the mean dose of 4.8 g/day. Major adverse events included constipation, hard feces, vomiting, etc.; however, none of the adverse events were serious or severe. Consequently, the superiority of bixalomer to placebo and its dose-dependency for treating hyperphosphatemia were confirmed (Clinical trial registration: NCT00505037).

Treatment of hyperphosphatemia with bixalomer in Japanese patients on long-term hemodialysis with gastrointestinal symptoms.

Bixalomer (Bix) is an amine-functional polymer, non-calcium-containing phosphate (P) binder, and has been clinically available in Japan recently. Bix is expected to cause fewer gastrointestinal (GI) side-effects as compared with sevelamer hydrochloride (SH), because of less expansion of Bix in the GI tract. In this prospective observational study, we evaluated changes in GI symptoms by the Gastrointestinal Symptom Rating Scale (GSRS) score in long-term hemodialysis (HD) outpatients with SH-associated GI symptoms who switched to Bix from SH. A total of 114 patients (age 63.7±10.8 year (mean±SD), female 65.5%, HD vintage 11.2±8.6 years, diabetes mellitus 27.4%) were enrolled. The GSRS score was checked at 0 and 12 weeks after the start of Bix. Bix was started at the initial dose of 750 mg/day, and then was titrated. Serum albumin, P and corrected calcium levels did not significantly change during Bix treatment. However, serum low-density lipoprotein-cholesterol and bicarbonate levels significantly increased during Bix treatment (P<0.001). In GSRS scores, total and domain-specific scores, including constipation, diarrhea, reflux and abdominal pain were significantly reduced at 0, 4, 12 and 24 weeks as compared with those at 0 weeks (P<0.05). This study shows that Bix was well tolerated and managed hyperphosphatemia effectively after switching from SH in Japanese patients on long-term HD. In addition, Bix might be less often associated with GI symptoms as compared with SH.

Comparison of the effects of Mylabris and Acanthopanax senticosus on promising cancer marker polyamines in plasma of a Hepatoma-22 mouse model using HPLC-ESI-MS.

A simple and sensitive method for the simultaneous determination of plasma concentrations of five polyamines in normal and Hepatoma-22 mice, and mice treated with Mylabris and Acanthopanax senticosus was developed by HPLC-ESI-MS. Male Kunming mice were divided into nine groups, a control group (inoculation without treatment), a positive group (Cyclophosphamide), treatment groups [Mylabris (4, 8, 16 mg/kg), Acanthopanax senticosus (6, 12, 24 g/kg)] and a normal group (without inoculation). Twenty-four hours after the last administration, plasma samples were collected. The derived polyamines were separated on a C(18) column by a gradient elution using methanol-water with excellent linearity within the range from 2.5 to 1000 ng/mL. Polyamines were confirmed as useful biochemical markers of hepatoma. The differences in anti-cancer therapeutic efficacy between Mylabris and Acanthopanax senticosus might contribute to the variability of polyamine levels in vivo. This HPLC-ESI-MS method was successfully applied to investigate the relationship between polyamines and cancer in mice and might be a useful method to test the activity of potential anti-tumor drugs.

Long-term oral polyamine intake increases blood polyamine concentrations.

Although the intracellular de novo synthesis of the polyamines decreases with age, there is no similar trend in blood polyamine levels, but rather there is wide individual variability. We hypothesized that dietary polyamines attenuate a decrease in blood polyamine levels with age and augment the previously observed individual variability. The effect of a polyamine rich diet, in both mice and humans, on blood polyamine concentrations was examined in this study. Jc1:ICR male mice were fed test diets containing 3 different polyamine concentrations. Healthy human male volunteers added 50 to 100 g of the polyamine-rich fermented soybean product, natto, to their daily intake. After 26 wk, the mean blood spermine concentration in mice receiving the test diet with high polyamine concentrations was 10.1+/-2.4 micromol/L, while the mean concentrations found in mice fed with a diet with normal or low polyamine concentrations were 5.2+/-0.9 and 4.7+/-0.5 micromol/L, respectively (p<0.05). A mean daily intake of 66.4+/-3.7 g (range=46.4-89.3 g) of natto for 2 mo by human volunteers increased the mean blood spermine concentration by a factor of 1.39 (n=10) (p<0.01), while in control volunteers (n=7), asked to exclude polyamine-rich foods from their diet, blood spermine concentration remained unchanged. The individual variability of blood polyamine levels was enhanced after polyamine intake in mice and, to a lesser extent, in humans. The long-term oral intake of enhanced polyamine diets increases blood polyamine levels in both mice and humans.

Polyamine levels in brain and plasma after acute restraint or water-immersion restraint stress in mice.

To investigate the relationship between polyamines and stress, we measured polyamine levels in the frontal cortex, hippocampus, hypothalamus, and plasma of mice after acute restraint or water-immersion restraint stress. In all parts of the brain, putrescine levels were elevated (139-157% of the control) 24 h after water-immersion restraint stress. In the case of restraint, however, elevation of the putrescine level (130% of the control) was detected only in the frontal cortex. Spermidine and spermine levels were unchanged or slightly reduced (80-85% of the control) in the brain 6 and 24 h after water-immersion restraint stress. There was no change in plasma polyamine levels at any time subsequent to the stress. Pretreatment with diazepam (5 mg/kg, i.p.) completely blocked the stress-induced putrescine increases. These results indicate that the magnitude of the putrescine increase is dependent upon the intensity of the stressor, and suggest that polyamine metabolism is linked to psychological stress.

A bitter diterpenoid furanolactone columbin from Calumbae Radix inhibits azoxymethane-induced rat colon carcinogenesis.

The modifying effect of dietary administration of a diterpenoid furanolactone columbin isolated from the crude drug Calumbae Radix (the root of Jateorhiza columba MIERS, Menispermacea) on azoxymethane (AOM)-induced was investigated in male F344 rats. Animals were initiated with AOM (three weekly subcutaneous injections of 15 mg/kg body weight) to induce colonic neoplasms. They were fed the experimental diets mixed with columbin (4, 20, and 100 ppm) for 4 weeks, starting 1 week before the first dosing of AOM and thereafter maintained on the basal diet without columbin. Additional experimental groups included the AOM alone group, the columbin alone group (100 ppm in diet for 4 weeks), and the untreated control group. Dietary feeding of columbin (4, 20, and 100 ppm) during the initiation phase of AOM-induced colon carcinogenesis reduced the incidence and multiplicity of colonic adenocarcinoma and the inhibition by feeding of 20 ppm (incidence: 20%, P=0.0242 and multiplicity: 0.20+/-0.40, P<0.02) and 100 ppm (incidence: 10%, P=0.0029 and multiplicity: 0.10+/-0.30, P<0.002) columbin was significant when compared with the AOM alone group (incidence: 55% and multiplicity: 0.55+/-0.50). Also, columbin administration in diet lowered the number of argyrophilic nucleolar organizer regions protein per nucleus in non-lesional colonic crypts and the blood polyamine content, which are reflected in cell proliferation activity. These results indicate chemopreventive ability of dietary columbin against chemically induced colon tumorigenesis when fed during the initiation phase, providing a scientific basis for chemopreventive ability of columbin against human colon cancer.

Citrus auraptene exerts dose-dependent chemopreventive activity in rat large bowel tumorigenesis: the inhibition correlates with suppression of cell proliferation and lipid peroxidation and with induction of phase II drug-metabolizing enzymes.

In our previous short-term experiment, Citrus auraptene inhibited the development of azoxymethane (AOM)-induced aberrant crypt foci, which are precursor lesions for colorectal carcinoma. In the present study, the possible inhibitory effect of dietary administration of auraptene was investigated using an animal colon carcinogenesis model with a colon carcinogen AOM. Male F344 rats were given s.c. injections of AOM (15 mg/kg body weight) once a week for 3 weeks to induce colon neoplasms. They also received diets containing 100 or 500 ppm auraptene for 4 weeks in groups of "initiation" feeding, starting 1 week before the first dosing of AOM. The diets containing auraptene were also given to rats for 38 weeks in groups of "postinitiation" feeding. At the termination of the study (38 weeks), dietary administration of auraptene caused dose-dependent inhibition in AOM-induced large bowel carcinogenesis. Auraptene feeding during the initiation phase reduced the incidence of colon adenocarcinoma by 49% at 100 ppm (P = 0.099) and 65% at 500 ppm (P = 0.0075). Auraptene administration during the postinitiation phase inhibited the incidence of colon adenocarcinoma by 58% at 100 ppm (P = 0.021) and 65% at 500 ppm (P = 0.0075). Also, the multiplicity of colon carcinoma was significantly reduced by initiation feeding at a dose level of 500 ppm (P < 0.01) and postinitiation feeding at a level of 100 and 500 ppm (P < 0.05 and P < 0.01, respectively). Feeding of auraptene suppressed the expression of cell proliferation biomarkers (ornithine decarboxylase activity and polyamine content) in the colonic mucosa and reduced the production of aldehydic lipid peroxidation [malondialdehyde and 4-hydroxy-2(E)-nonenal]. In addition, auraptene increased the activities of Phase II drug-metabolizing enzymes (glutathione S-transferase and quinone reductase) in the liver and colon. These findings suggest that the inhibitory effects of auraptene on AOM-induced colon tumorigenesis at the initiation level might be associated, in part, with increased activity of Phase II enzymes, and those at the postinitiation stage might be related to suppression of cell proliferation and lipid peroxidation in the colonic mucosa.

Suppression of azoxymethane-induced rat colon carcinogenesis by dietary administration of naturally occurring xanthophylls astaxanthin and canthaxanthin during the postinitiation phase.

The modulating effects of dietary feeding of two xanthophylls, astaxanthin (AX) and canthaxanthin (CX) during the postinitiation phase on colon carcinogenesis initiated with azoxymethane (AOM) were investigated in male F344 rats. Animals were initiated with AOM by weekly s.c. injections of 15 mg/kg body wt for 3 weeks and then they were fed the diets containing AX or CX at concentrations of 100 and 500 p.p.m. for 34 weeks. The others contained the groups of rats treated with AX or CX alone and untreated. At the end of the study (week 37), the incidence and multiplicity of neoplasms (adenoma and adenocarcinoma) in the large intestine of rats initiated with AOM and followed by AX or CX containing diet at a high dose (500 p.p.m.) were significantly smaller than those of rats given AOM alone (P < 0.001). In addition, AX or CX feeding significantly inhibited the development of aberrant crypt foci induced by AOM. Dietary exposure to AX or CX also decreased cell proliferation activity as revealed by measuring 5'-bromodeoxyuridine-labeling index as crypt cells, colonic mucosal ornithine decarboxylase activity and blood polyamine levels. These results indicate that AX and CX are possible chemopreventers for carcinogenesis of colon in addition to urinary bladder and oral cavity and such effects may be partly due to suppression of cell proliferation.

Acute and chronic hyperbaric oxygen exposure in humans: effects on blood polyamines, adrenocorticotropin and beta-endorphin.

Plasma beta-endorphin, adrenocorticotropin (ACTH) and blood polyamine (spermidine and spermine) concentrations were evaluated in healthy adult male athletes undergoing hyperbaric oxygen exposure for 10 days (2.8 atm, 100% O2, 60 min daily). In the "acute phase", corresponding to the first day of treatment, and in the "acute in the chronic phase", corresponding to the values obtained on the 5th and 10th days after 60 min of hyperbaric O2, both ACTH and beta-endorphin levels increased significantly, whereas no variations were observed for polyamine concentrations. In the "chronic phase", corresponding to the basal values of the 5th and 10th days of treatment, we found a different pattern. In fact, the concentration of polyamines showed a remarkable enhancement, while ACTH and beta-endorphin levels remained unchanged. No significant variations were observed during hyperbarism with air. These results demonstrate different modifications of polyamines and beta-endorphin and ACTH in subjects submitted to hyperbaric oxygen exposure.

Effect of dietary zinc deficiency and the associated drop in voluntary food intake on rat erythrocyte membrane polyamines.

The effect of dietary zinc deficiency in the rat on the free (noncovalently bound) polyamine concentrations in erythrocyte membranes, in erythrocyte cytosol and in the blood plasma were determined. Weanling male Wistar rats were fed an egg white-based diet containing less than 1.0 mg Zn/kg diet for 3 wk ad libitum. Control rats were either pair-fed or ad libitum-fed the basal diet supplemented with 100 mg Zn/kg diet. Tissue fractions were extracted with 0.2 M perchloric acid and polyamines were measured in the soluble fraction by dansylation, thin-layer chromatography and fluorescence spectrophotometry of the isolated dansylated polyamines. The depressed food intake associated with dietary zinc deficiency caused significantly (P less than 0.05) lower plasma spermidine, erythrocyte cytosol putrescine, spermidine and spermine and erythrocyte membrane spermidine concentrations. In addition, the depressed food intake caused significantly lower spermidine-spermine ratios in the erythrocyte membrane and cytosol and in blood plasma. Dietary zinc deficiency per se caused significantly (P less than 0.05) higher plasma spermidine and spermine and erythrocyte membrane spermine concentrations and significantly lower spermidine-spermine ratios in erythrocyte membrane and cytosol than in pair-fed, zinc-adequate controls.